A salt is a random addition to a password to make the hashed password less susceptible to a lookup table attack

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9
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3answers
1k views

Is too long salt reducing security of stored password hash?

Suppose we have statistically 7-8 characters long passwords. Is appending a 200-characters long salt less secure than 5-characters salt, because of similiar hash function inputs? I was wondering, ...
194
votes
6answers
25k views

How to store salt?

Nowadays, if we expect to store user password securely, we need at least do the following thing $pwd=hash(hash($password) + salt) then store $pwd in your system instead of the real password. I have ...
126
votes
8answers
12k views

Why are salted hashes more secure?

I know there are many discussions on salted hashes, and I understand that the purpose is to make it impossible to build a rainbow table of all possible hashes (generally up to 7 characters). My ...
0
votes
1answer
77 views

Publicly Available API + Sensitive ID/Key Transmission Over HTTP

I've run into a predicament... I'm developing a mobile application that utilizes a server for various things. One portion is that it stores an id/key pair related to accessing and processing ...
8
votes
6answers
899 views

Is it useful to protect hashed password with encryption?

Imagine that I am hashing the users' passwords with a random, long enough, salt, using key stretching, and a secure hash. Would it be more secure to finally encrypt the hash with a symmetric key?
3
votes
1answer
239 views

Perfectly Robust Hashing Scheme, or Completely Over-Engineered?

This is going to get long, so prepare. Basis of the question is, Do all these steps improve security, or am I completely overthinking the problem? Are my assumptions/thought process valid? We all ...
5
votes
2answers
680 views

Can the IV + Salt be the same?

During my encryption app i've got the password creation bit: PBEKeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 10000, keyLength); and later on the actual encryption part: ...
8
votes
5answers
1k views

Should I remotely store my salt? [duplicate]

When users register on my site, I want to store their username and hashed password in my database. When I hash that password, I'm going to salt it using PHP. The issue is, I don't want to store the ...
5
votes
2answers
614 views

Authentication: Username (email) and password hashed together in one database field

I am currently developping a platform with a PHP framework for our client. The head of the client's IT department wants us to handle authentication with one database field containing ...
1
vote
2answers
117 views

Is it a good idea to use the user's username as a salt when hashing a password like hash(username_str + password_str)?

I'm helping my friend with hashing his passwords, and I've a question - Should he use one secret string as salt for hashing or is it better to have each user its own salt for hashing? Consider these ...
-2
votes
3answers
122 views

My friend hashes passwords with SHA512 algorithm without salt. How do I convince him that he needs to add salt?

Today I discovered something incredibly stupid - my friend hashes user passwords with sha512 algorithm without a salt. I immediately raised this issue to him but he said he wants to see anyone crack a ...
2
votes
1answer
112 views

How to autenticate properly in Java

I have to write some login module for Java EE application. Previously i was using JBoss security - provided login and password, called HttpServletRequest with login method and JBoss security did the ...
3
votes
3answers
484 views

Accepting other similar passwords when storing a salted, hashed password

If a website stores passwords as a salted hash, is it reasonable to accept similar passwords as correct? For example, given the password stackexchange, does it dramatically decrease security if the ...
2
votes
1answer
203 views

MySQL Authentication Hash Cracking

I'm currently conducting research regarding MySQL server remote authentication. I've captured unencrypted, uncompressed authentication packets between the client and the server where the username is ...
1
vote
2answers
125 views

Search on hashed data

We have a request to encrypt customer personal data (e-mail, address etc.) We use MySQL which does not have any TDE like MS SQL or Oracle. So along with encrypting data we need to preserve ...
3
votes
2answers
173 views

Is there a strong reason to salt and hash passwords when password reuse is not an issue?

I am dealing with a system (in development) that uses randomly generated (not user provided), unique, strings to authenticate services that will consuming an API. Right now, these strings are stored ...
4
votes
1answer
122 views

Using random number to salt passwords

in a project I have, I'm salting passwords with 3 salts at the moment... Static salt - hard-coded into the source-code. Randomly generated salt (using a function designed for generating password ...
12
votes
2answers
586 views

How Does A Random Salt Work? [duplicate]

I don't understand how using a random salt for hashing passwords can work. Perhaps random salt refers to something other than hashing passwords? Here is my thought process: The salt is used to add ...
80
votes
6answers
25k views

Password Hashing add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
-2
votes
1answer
72 views

Salt and password [closed]

Reading the doc for setting the password, the command is : python -c "import crypt; print crypt.crypt('password', '\$6\$SALTsalt')" SALTsalt is the 8-character crpytographic salt. Valid characters in ...
0
votes
1answer
67 views

Good way to make a secure token for logged out users

I work for a firm that has a marketplace on the web. We want to make a link with a token that stops an ad on the marketplace without the user being logged in. Someone suggested that we make a token ...
2
votes
4answers
708 views

Using last characters of hash as salt [duplicate]

In a recent discussion somebody mentioned the following hashing scheme: passHash = sha256(password) saltedHash = sha256(passHash+passHash.substr(-10) finalHash = sha256(secret+saltedHash) The ...
3
votes
2answers
152 views

Search on encrypted data of multiple users

I want to implement a search over encrypted data. I found a blogpost, which explains 3 methods. One method is to use deterministic encryption, which I'm trying to implement. But my use case is a ...
0
votes
1answer
117 views

Save password on user-side for autologin

If a user wants to login to a system/server, it's recommended to have the hashed&salted password saved in a database, along with its salt. So the user wants to login, types in the password, ...
1
vote
2answers
98 views

Is it unsafe to hash one password with more than one salt?

I'm asking my question here since I was not able to find an answer anywhere. I have written a piece of software which stores pretty delicate passwords. I have used BCrypt as hashing algorithm with an ...
-1
votes
2answers
89 views

How does salting increase security? [duplicate]

I'm currently going through a course on software security. I've recently been introduced to the idea of password salting, where a random value is concatenated to a password prior to being hashed and ...
70
votes
8answers
9k views

Convincing my manager to use salts

My manager says we don't need to salt our passwords because people are not likely to use the same password because they all have different native languages, in addition to the websites they are active ...
0
votes
3answers
61 views

How to secure Password and Salt on a deployed application

I have a question regarding one step of protection more than salt/hash. I work on an application that is distributed to many clients and then deployed on their networks. If I set a password on one ...
20
votes
5answers
2k views

When hashing passwords, is it ok to use the hashed password as the salt?

I don't like this idea. But I can not come up with a technical argument against it. Can somebody explain it to me? The basic idea is: $passwd = 'foo'; $salt = hash($passwd); $finalHash = hash($passwd ...
4
votes
2answers
222 views

Would re-salting passwords regularly in-/decrease security?

What are the (dis)advantages of re-salting a user's password regularly, e.g. weekly (or at their next login once week since the last re-salting)? The basic idea would be that users who regularly log ...
8
votes
3answers
4k views

How often do two users use the same password

If no two users use the same password, then in theory salting the password hash is not needed. How often, in practice, do two users have the same password?
2
votes
2answers
110 views

Breach informing

I am a staff member of a large fanfic site, but not the head administrator with control over the site itself. Recently, we had a security breach and the databases were copied, which included the ...
3
votes
2answers
186 views

MySQL ENCRYPT salt is not random?

I know there's little reason to still use ENCRYPT() nowadays, what with bcrypt being almost ubiquitous and MySQL providing better hashes such as SHA1. But while dabbling with ENCRYPT() on MySQL ...
0
votes
2answers
166 views

When I reset my password for my Microsoft account, how do they know what password I've used before?

Assumption used: all password that I've used have been salted with some random elements before hashed and stored somewhere in their database. If my previous password exists only as salted-hashes in ...
2
votes
1answer
191 views

Any reason I shouldn't be salting and hashing before putting through bCrypt?

I've been reading up on password storage and such, and have come to the conclusion that I need to be using bCrypt. I've got an implementation working correctly, but I'm wondering the best way to move ...
55
votes
3answers
18k views

How can I create a password that says “SALT ME!” when hashed?

How can I create a password, which when directly hashed (without any salt) with md5 will return a string containing the 8 characters "SALT ME!". The hope is that a naive developer browsing through his ...
2
votes
1answer
123 views

How difficult it is to solve a salt if knowing the original data and the hash output that uses the SHA-2 algorithm

I am reading the documentation for Kentico where it describes using hashes to validate query strings ...
12
votes
6answers
2k views

Do salts have to be random, or just unique and unknown?

First of all, my motive is to avoid storing the salt in the database as plain text. As far as this question is concerned, the salt is not stored in the database. After discussion in comments and in ...
5
votes
3answers
782 views

How often should I reset my salt?

I'm thinking of implementing a salt recycling scheme on my user credentials database. The motivation behind this decision is that even if the attacker manages to get his hands on the database and has ...
2
votes
4answers
393 views

How does a system authenticate a user using a hash function, after it has been salted?

I don't really understand how salting works. I read the Wikipedia article, but I still don't understand how can a system authenticate a salted hash? Let's say a user chooses a password. It's randomly ...
2
votes
4answers
107 views

Random salt - necessary for a single user?

Based on: http://security.stackexchange.com/a/33520/42220 and http://security.stackexchange.com/a/41630/42220 I can see the benefits of a completely random salt per user. If I am implementing an ...
1
vote
3answers
1k views

Is Salt, IV and Key necessary when encrypting password in a database using AES? If so, how should they be used?

Imagine I have a website with user accounts. I want to authenticate users, so I need to know if the password they provide matches the one stored in my database. To protect the passwords from prying ...
2
votes
1answer
233 views

php crypt - trailing dollar sign - extract only the salt part from hash - padding the salt

I am reading up on PHP's crypt() function. I have a few questions on it - What is the significance of the trailing '$' sign at the end of the salt string that I see in most examples. The manual ...
1
vote
1answer
236 views

Hash Security of Windows 7 Password

I need to find some materials about how Security Accounts Manager(SAM) works in windows 7+. I am confused with the storage format of hashed value. Many materials (such as, 1) tells me that it uses ...
1
vote
2answers
128 views

How to use ESSIV to avoid seeing repeated patterns?

I'm trying to implement an encrypted file-system. The file-system consists of 512-byte sectors. I encrypt/decrypt the contents of a sector as follows: Compute the SHA256 sum of the user password. ...
1
vote
3answers
610 views

What is the correct way to make a password salt?

I've made the below function to make a completely random 64 character long hash function password_salt($password){ $salt = hash("sha512", mt_rand(1,100000) . strtotime("now") . $password . ...
3
votes
2answers
1k views

How weak is MD5 as a password hashing function ?

A professor told us today, that MD5 is weak. I understand his chain of thought but pointed out, that IMHO MD5 is a good way to go if you would use a long (even really long) dynamic salts and static ...
0
votes
2answers
93 views

How do you overcome the problem of the salt being public and known by the attacker? [duplicate]

I believe that when adding a salt to the password you need to store the values so you can compute the hash again. But, what does happen if the attacker get the salt? How is it possible to add value ...
0
votes
3answers
119 views

Using a Hash as a Salt? [duplicate]

Ive done a bit of reading on the subject of Hashes and Salts and I came up with an idea for a salting scheme but I wanted to check it with some people more learned than myself. My basic idea is to ...
1
vote
0answers
59 views

How do I determine whether a Linux-based router still has the default password? [duplicate]

My goal is to check if the password used by admin is the default password. I work on a Linux-based router. I know the password is stored as a hashed value in /etc/passwd. In generic Linux machines, ...